PROJECT SUMMARY/ABSTRACT Dr. Natalie A. Bello is a cardiologist whose long-term career goal is to generate and disseminate empiric evidence to reduce the burden of maternal-fetal morbidity and mortality resulting from hypertensive disorders of pregnancy (HDP). She seeks a K23 Career Development Award to attain this goal, and has assembled a multidisciplinary team of senior investigators in hypertension (HTN) (Drs. Daichi Shimbo and Suzanne Oparil), out-of-clinic blood pressure (BP) measurement including home BP monitoring (HBPM) (Drs. Shimbo and Joseph Schwartz), epidemiology (Dr. Paul Muntner), maternal-fetal medicine (Drs. Alan Tita and Ronald Wapner), and biostatistics (Drs. Schwartz and Muntner). Dr. Bello?s training will consist of four modules: (1) Hypertensive Disorders of Pregnancy, (2) Research Aspects of the Diagnosis and Treatment of HTN, (3) Advanced Study Design and Statistical Analysis in HTN, and (4) Research Dissemination and Transition to Independence. HDP, including chronic and gestational HTN, are associated with substantial maternal-fetal morbidity and mortality. The accurate determination of BP in pregnant women with chronic and gestational HTN is essential, as both under- and over-treatment of HTN may result in harm to the mother and/or fetus. Traditional clinic BP (CBP), which involves a healthcare provider measuring BP, is a poor surrogate for ecological BP in the naturalistic environment. Compared to CBP, out-of-clinic BP on HBPM better estimates ecological BP, and thus may be a superior measure of placental perfusion. Although these data suggest that HBPM has an essential role in the management of chronic and gestational HTN, there are several knowledge gaps that limit the widespread use of HBPM in this population. The minimum number of days of HBPM to reliably estimate mean home BP, and the long-term adherence to HBPM during pregnancy among women with chronic and gestational HTN are unknown. Finally, studies of non-pregnant individuals show that compared to traditional CBP, CBP measured using an automated device in the absence of a healthcare provider (unattended CBP) may better approximate out-of-clinic BP. In the proposed project, the minimum number of days of HBPM needed to provide a reliable estimate of mean home BP (Primary Aim 1) and the long-term adherence to HBPM during pregnancy (Primary Aim 2) will be determined. Whether mean unattended CBP versus traditional CBP is closer to mean home BP (Secondary Aim) will also be assessed. Primary Aim 1 and Secondary Aim will be addressed among 105 pregnant women (<34 weeks gestation) with chronic and gestational HTN who will undergo HBPM for 14 days with traditional and unattended CBP measurement (Study 1). Primary Aim 2 will be addressed among 75 pregnant women with chronic and gestational HTN who will undergo HBPM daily from the second trimester (gestational week 20-26) through delivery (Study 2). These data will inform Dr. Bello?s program of research on HDP, and will provide the foundation for her to design larger outcomes-based studies (R01) examining the role of HBPM and CBP in pregnancy. 1